In the assembly of electronic components, a major threat to the quality of such assemblies is the electrical potential difference existing between the electrical part assembly and the operator which may cause the part to be damaged. The fundamental solution to this electrostatic discharge problem in the work place is to provide a means to directly ground the operator to zero electrical potential. Wrist strap devices are the most common prior art means to ground operators at their work stations, but these devices suffer from the disadvantage of limiting operator movement between work stations.
As such, various foot wear has been developed in the prior art having the capability of conducting electrical charges to ground while still offering operators, supervisory personnel, individuals on tours, etc., mobility throughout the work place. The typical prior art heel grounders for comprise a unitary conductive rubber "cup" that fits over the heel of a shoe, and a conductive fabric strap which extends therefrom to be in electrical contact with the wearer's leg. Such heel grounder typically is held on the wearer's foot by an elastic strap or a hook-and-loop (Velcro.TM.) fastening arrangement. Such devices are relatively durable, usually lasting several months, but are also costly. Additionally, such devices often do not accommodate differing size and configurations of worker's shoes which vary greatly, especially between men and women.
Because the heel grounder is in intimate contact with the wearer, heel grounders are generally not passed from one person to another. The heel grounder for a visitor or a temporary employee is usually discarded, regardless of its condition. Disposable short-term use devices have been developed for transient visitors or personnel, typically consisting of a conductive strip which adheres to the heel of the shoe and is tucked into the shoe or sock to make contact with the wearer. These devices tend to become easily damaged, however, and thus their utility is limited.
Recognizing that the conductive rubber "cup" portion of conventional heel grounder devices may become soiled from the conductive flooring over which the operator moves about, it has been proposed to add flush head metal rivets or other enhancements to insure electrical contact with the floor. Such devices may cause discomfort, however, as the operator walks over hard flooring, and additionally add to the cost of manufacture of the device.
Although the available prior art heel grounders have proven generally suitable for their intended purposes, based on the inherent deficiencies discussed above, it is desirable to provide a heel grounder offering improved fitting and wearing to the user, and further having replaceable components to meet the needs of a single user over time or the needs of multiple users.